|Location|Building|Year|km|Monument|
|---|---|---|---|---|
|Bischofsheim|Station building|1958|08.25|*|
|Rüsselsheim|Linesmen house|1863|12.80|*|
|Raunheim|Station building|1863|15.87|*|
|Raunheim|Linesmen house|1863|17.39|*|
|Kelsterbach|Rail bridge|1863|21.75||
|Kelsterbach|Linesmen house|1863|23.60|*|
|Kelsterbach|Station building|1863|23.81|*|
|Stadion|Station building|1879|31.37|*|
|Niederrad|Station building|1882|33.19|*|
|Sachsenhausen|Rail bridge|1864|34.47||

Question: what is the average of years
Answer: 1876